PFF is going through the entire league and grading players drafted over the last 4 years. The link displays a pretty fair analysis of all the players that have been drafted over that span. Although I think you could quibble with a couple of his placements, overall it seems pretty accurate.
Here's the summary:
"You can’t buy yourself much more leeway than what the Falcons did in 2008 when they drafted a class that changed the fortunes of the franchise. Indeed, it’s extremely rare to find six players from one draft group to have played so much for a team, especially one that snared them a franchise quarterback. Since then, it’s been a mixed bag, with the 2009 group largely being disappointing and 2010 looking far more promising (especially on the defensive side of the ball). If there’s one criticism, it’s that Atlanta needs a bigger impact from some of its draft selections, as opposed to the solid, consistent type they’ve been getting."